A/an _____ valve is needed to keep a hot water heating system with a closed expansion tank automatically filled and under proper pressure.
a. Feedwater control
b. Pressure relief
c. Expansion
d. Pressure reducing
e. Hydramotor
Answer: D
A/an _____ valve is needed to keep a hot water heating system with a closed expansion tank automatically filled and under proper pressure.
a. Feedwater control
b. Pressure relief
c. Expansion
d. Pressure reducing
e. Hydramotor
Answer: D